Laravel 4：不存在的地方
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Laravel 4: Where Not Exists
提问by sterfry68
I need my model to return only those records from one table where a matching record does not exist in another table. I was thinking that the solution might be with Query Scopesbut the documentation only scratches the surface. So my SQL would look something like this:
我需要我的模型只返回一个表中的那些记录，而另一个表中不存在匹配的记录。我在想解决方案可能与查询范围有关，但文档只是触及了表面。所以我的 SQL 看起来像这样：
SELECT *
FROM A
WHERE NOT EXISTS (SELECT A_id FROM B
WHERE B.A_id = A.id)
Here are my tables:
这是我的表：
A
-------------
| id | name |
-------------
B
--------------------
| id | A_id | name |
--------------------
Probably unnecessary but here are my models. Model for A:
可能没有必要，但这是我的模型。A 型号：
class A extends Eloquent{
public function B(){
return $this->hasOne('B', 'A_id', 'id');
}
}
Model for B:
B 型号：
class B extends Eloquent{
public function A(){
return $this->belongsTo('B', 'A_id', 'id');
}
}
回答by marcanuy
Something like
就像是
A::whereNotExists(function($query)
{
$query->select(DB::raw(1))
->from('B')
->whereRaw('A.id = B.id');
})
->get();
